2012 Annual Report
2. Determine relationships between cover crop selection, crop residue addition/removal, C loss pathways, and C sequestration to develop management practices that increase profile soil organic C (SOC) contents and maintain/improve soil microbial populations related to plant productivity. 2a. Determine the effects of sandy coastal soils and their management such as harvest frequency and N fertilizer rates on the following: a) switchgrass yields, b) improvements of in-profile SOC, c) C sequestration, d) switchgrass thermal bioenergy value, and e) nutrient removal with harvested biomass. 2b. Determine amount of residue that can be removed from a Coastal Plain soil while still maintaining crop productivity. 2c. Assess management practices that increase SOC contents in long-term tillage experiments.
Development of designer biochar tailored to improve specific soil properties: Biochar can be designed for specific soil improvements by changing feedstock blending ratios, pyrolysis temperatures, and by pelletization. In response to Objective 1, designer biochars incubated in soil were effective at improving soil quality. These results corroborate that biochars can be tailored to modifying specific soil properties.
Response of soil microbial communities to biochar: Under Objective 1, biochar’s impact on soil microbial genetics was investigated by incubating soil with switchgrass biochar. The genes associated with microbial nitrogen cycling were extracted and quantified. These genes showed a stimulation in response to biochar implying that switchgrass biochar was not detrimental to soil microbial communities.
Improvement in soil profile soil organic carbon contents using switchgrass: In response to Objective 2, a switchgrass field study revealed that profile (0 to 90-centimeter deep) soil organic carbon contents increased due to the crop’s deep root system. Annual soil coring revealed that soil organic carbon contents increased within the first year and were maintained throughout the study. Under variable climatic conditions, switchgrass was capable of improving soil carbon sequestration levels while also providing sufficient crop biomass for bioenergy production.
Sustainable corn residue removal in sandy agricultural soils: Bioenergy production in the Coastal Plain region requires crop residues, but some residue must be returned to soil for nutrient replenishment. In response to Objective 2, crop yields, compositional analyses, and soil fertility levels are measured from plots under different rates of residue removal. Crop yields in three of the project’s four years were variable, but plant compositional and thermal energy values have remained near steady. Harvesting crop biomass can remove plant nutrients concomitantly lowering soil nutrient levels.
Long-term increases in soil organic carbon with conservation tillage: In response to Objective 2, the amount of carbon sequester was examined in conservation tillage systems. In these side-by-side conservation and conventional tillage plots, conservation tillage has shown a surface (0 to 4-centimeter depth) carbon-enriched layer formed over 25 yrs; conservation tillage promotes slow carbon accumulation (< 0.1% per yr). This long-term study is important for scientists because it demonstrates rates of carbon sequestered under different tillage practices.
Raczkowski, C.W., Mueller, J.P., Busscher, W.J., Bell, M.C., Mcgraw, M.L. 2012. Soil physical properties of agricultural systems in a large-scale study. Soil & Tillage Research. 119:50-59.
Novak, J.M., Busscher, W.J., Watts, D.W., Amonette, J., Ippolito, J.A., Lima, I.M., Gaskin, J., Das, K.C., Steiner, C., Ahmedna, M., Rehrah, D., Schomberg, H.H. 2012. Biochars impact on soil moisture storage in an Ultisol and two Aridisols. Soil Science. 177(5):310-320.
Busscher, W.J., Novak, J.M., Ahmedna, M., Niandou, M. 2011. Physical effects of organic matter amendment of a southeastern USA coastal loamy sand. Soil Science. 176(12):661-667.
Dell, C.J., Novak, J.M. 2012. Cropland management in the eastern united states for improved soil organic carbon sequestration. In: Liebig, M.S., Franzluebbers, A.J., Follett, R.F., editors. Managing Agriculutral Greenhouse Gases: Coordinated Agricultural Research through GRACEnet to Address our Changing Climate. San Diego, CA: Elsevier. p. 23-41.
Ippolito, J.A., Novak, J.M., Busscher, W.J., Ahmedna, M., Rehrah, D., Watts, D.W. 2012. Switchgrass biochar effects two aridisols. Journal of Environmental Quality. 41(4): 1123-1130.
Mitra, S., Wielopolski, L., Omonode, R., Novak, J.M., Frederick, J., Chan, A. 2012. Non-invasive measurements of soil water content using a pulsed 14 MeV neutron generator. Soil & Tillage Research. 120:130-136.
Spokas, K.A., Novak, J.M., Venterea, R.T. 2012. Biochar’s role as an alternative N-fertilizer:Ammonia capture. Plant and Soil. 350(1):35-42.
Spokas, K.A., Cantrell, K.B., Novak, J.M., Archer, D.W., Ippolito, J.A., Collins, H.P., Boateng, A.A., Lima, I.M., Lamb, M.C., Mcaloon, A.J., Lentz, R.D., Nichols, K.A. 2012. Biochar: A synthesis of its agronomic impact beyond carbon sequestration. Journal of Environmental Quality. 41(4):973-989.
Spokas, K.A., Novak, J.M., Stewart, C.E., Cantrell, K.B., Uchimiya, S.M., Dusaire, M.G., Ro, K.S. 2011. Qualitative analysis of volatile organic compounds on biochar. Chemosphere. 85(5):869-882.
Uchimiya, M., Cantrell, K.B., Hunt, P.G., Novak, J.M., Chang, S. 2012. Retention of heavy metals in a Typic Kandiudult amended with different manure-based biochars. Journal of Environmental Quality. 41:1138-1149.
Johnson, J.M., Novak, J.M. 2012. Sustainable bioenergy feedstock production systems: Integrating carbon dynamics, erosion, water quality, and greenhouse gas production. In: Liebig, M.A., Franzluebbers, A.J., Follett, R.F., editors. Managing Agricultural Greenhouse Gases: Coordinated Agricultural Research through GRACEnet to Address Our Changing Climate. San Diego, CA: Elsevier. p. 111-126.